There is a SMS API and NOKIA UI API documentation in a www.forum.nokia.com under java section -> documents.
Currently voice activated dialling by using MIDP is not possible.
Nokia has launched 5 MIDP Java technology supporting phones.In addition to standard MIDP implementation, the Nokia has defined API extensions that enhance the developer's capability of delivering good applications for Nokia devices. The following features are implemented in the Nokia UI API:
1. Low level access to image pixeldata
2. Transparency support
3. Full screen drawing
5. Vibration and device lights control
3410 NOKIA UI API, NOKIA SMS API
6310i NOKIA UI API
6610 NOKIA UI API
7210 NOKIA UI API
7650 NOKIA UI API, not vibra and no back lights control supported